The security of homes, offices and rooms of hotels and motels against unlawful entry is a major concern. Particularly, in the case of hotels, the security of a room is dependent on key and lock arrangements and the effectiveness is determined by how carefully keys to such locks have been controlled. Because of lost keys and the possibility of duplicating keys possession of keys to such room is uncertain.
Devices have been provided for adding security to established door knob installations which is under the control of the individual and may be used with selected doors. Among such devices are those for disabling the door knob and preventing access to the lock portion which frequently is incorporated in the knob. Unfortunately such devices tend to become complex to have multiple parts making it difficult to put the arrangement into operation and are easily tampered with and overcome so that the door knob is available for operation and unlocking.
It is an object of the invention to provide security device which is easily attachable to rotary type door knob to prevent operation of the door knob and access to the key and lock that may be incorporated in the door knob.
It is another object of the invention to provide a security device which can be easily installed on the door knob with one hand if necessary.
Another object of the invention is to provide such a security device which utilizes a minimum of simple parts.
Yet another object of the invention is to provide a security device which can be applied to doors which are not otherwise provided with locks.
The objects of the invention are attained by a security device for a rotatable door knob in which an inner body member has a generally cylindrical configuration including a pair of spaced end walls which are joined together in spaced apart relationship to receive a knob there between and an outer body member having a generally cylindrical configuration to receive the inner body member and door knob. The inner body member has a lock member protruding through and end wall of the outer body member to receive a lock device to prevent separation of the two body members and at the same time to permit relative rotation between the body members and relative to the door knob to prevent actuation of the door knob and also to prevent access to the key portion of the door knob.
These and other objects and advantages of the invention will become apparent from the following description taken together with the accompanied drawings.